AB0599 THE VALUE OF ULTRASOUND IN GCA FOLLOW-UP: RESULTS FROM A SCOTTISH SINGLE CENTRE.
Authors: A. Melville, A. Ciechomska
Journal: Annals of the Rheumatic Diseases (2022)

Background Ultrasound (USS) is important diagnostically in GCA, but its value during follow-up is unclear 1 . In our centre, ad hoc follow-up USS has been performed routinely. Objectives To describe how USS appearances i) changed over time (at defined timepoints), ii) correlated with clinical relapse (at any time), iii) were affected by tocilizumab. Methods Patients diagnosed with GCA in NHS Lanarkshire, November 2018 - October 2021, were included. Treatment was in accordance with international guidelines 2 . Follow-up visit data included clinical status (remission, stable, relapse), treatment, and (when USS performed) temporal artery (TA) and axillary artery (LV) intima media thickening (IMT) (TA+ = IMT ≥0.5MM; LV+ = IMT &gt;1mm). Follow-up USS were compared to baseline, pre-relapse or pre-tocilizumab. Results 55 patients were diagnosed with GCA; mean (SD) age 73.1 (8.0) years; 31 female (56.4%). Mean (SD) follow-up was 63.8 (40.6) weeks. All patients had baseline USS [48 positive (TA+ or LV+)], 7 negative; 36 (65.5%) had ≥1 follow-up USS. 7 patients had USS at 6-12 weeks ; all were clinically stable; all had positive baseline USS; at 6-12 weeks, 3/7 remained TA+, 1/7 remained LV+ (TA-LV+). 25 patients had USS at 16-36 weeks ; 9/25 were in remission, 11/25 stable, 5/25 relapsing. Of remission patients, 7/9 had positive baseline USS; at 16-36 weeks, 2/7 remained TA+. Of stable patients, all had positive baseline USS; at 16-36 weeks, 4/11 remained TA+, 3/11 remained LV+. Of relapsing patients, 5/5 had positive baseline USS; at 16-36 weeks, 2/5 remained TA+, 1/5 LV remained LV+. 15 patients had USS at 42-62 weeks ; 8/15 were in remission, 3/15 stable, 4/15 relapsing. Of remission patients, 7/8 had positive baseline USS; at 42-62 weeks, 3/7 remained TA+. Of stable patients, 3/3 had positive baseline USS; at 42-62 weeks, 1/3 was TA-LV+, 1/3 remained TA+LV+. Of relapsing patients, 4/4 had positive baseline USS (3/4 TA+, 1/4 LV+); at 42-62 weeks, all were TA-LV+. The Table 1 below provides additional detail for each timepoint. 11 patients in total had clinical relapse (any time) and contemporaneous USS ; mean (SD) time to relapse was 36.6 (18.3) weeks; median (IQR) prednisolone dose 7mg (4,9). At relapse, 2/11 were TA+LV+, 6/11 LV+, 3/11 TA-LV-. Comparing relapse USS to most recent USS pre-relapse, 4/11 were newly LV+, while other positive findings were seen previously. 11 patients treated with tocilizumab had ≥1 USS post-initiation [at mean (SD) 27.1 (16.7) weeks]. 5/11 were LV+ pre-tocilizumab, 6/11 TA+. At follow-up, all were in remission or stable; 4/5 remained LV+, 4/6 remained TA+. Table 1. Follow-up and corresponding baseline ultrasound results, at defined timepoints, grouped by clinical status. Baseline ultrasound Follow-up ultrasound Time Clinical status N a TA+LV- LV+TA- TA+LV+ TA-LV- TA+LV- LV+TA- TA+LV+ TA-LV- 6-12 week All stable 7 6 0 1 0 3 1 0 3 16-36 week All 25 17 0 6 2 6 4 0 15 Remission 9 6 0 1 2 2 0 0 7 Stable 11 7 0 4 0 4 3 0 4 Relapse 5 4 0 1 0 2 1 0 2 42-62 week All 15 11 1 2 1 3 5 1 6 Remission 8 6 0 1 1 3 0 0 5 Stable 3 2 0 1 0 0 1 1 1 Relapse 4 3 1 0 0 0 4 0 0 a.Number of patients scanned. Conclusion While many patients had rapid normalisation of USS changes with treatment, others remained abnormal despite stable disease or remission, including at approx. 12 months follow-up. Ad hoc follow-up scans therefore appear unreliable in isolation, but the value of systematic longitudinal scanning warrants further study. Emergence of LV positivity was seen in several cases of relapse and may characterise an evolution in disease phenotype. Positive USS findings largely persisted at approx. 6 months despite disease control on tocilizumab. References [1]Dejaco et al, ARD 2018. [2]Hellmich et al, ARD 2020. Disclosure of Interests Andrew Melville Grant/research support from: Dr Melville is a MRC GSK EMINENT clinical training fellow, with project funding outside the submitted work., Anna Ciechomska Speakers bureau: Dr Ciechomska has received speaker, travel and registration fee sponsorship from Novartis, Abbvie, Chugai Pharma, Colgene, Roche and Lilly.